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排序方式: 共有738条查询结果,搜索用时 156 毫秒
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Maria Di Bello Valeria Lucchini Stefania Chiari Roberto Colleoni Nicoletta Colombo Alberto Mantovani Paola Allavena 《Cancer immunology, immunotherapy : CII》1988,27(1):63-68
Summary Expression of HLA-DR antigens by purified preparations of human ovarian carcinoma cells freshly isolated from surgical specimens was examined in parallel with the capacity of tumor cells to elicit a blastogenic response from autologous lymphocytes in mixed lymphocyte-tumor culture (MLTC) assay. Of 21 tumor preparations, 11 (52%) reacted with monoclonal antibodies 279 and/or 949 specific for a monomorphic determinant of HLA-DR antigens, with heterogeneous positivity, ranging between 30% and 95%. In this series of patients positive MLTC occurred in 8/21 individual experiments. The HLA-DR expression was proportionally similar in tumors giving positive MLTC (4/8=50%) and negative MLTC (7/13=53%). The lack of correlation between DR expression on tumor cells and stimulatory activity in autologous MLTC and the fact that DR-negative tumors could induce lymphocyte stimulation, support the hypothesis that blastogenesis occurs upon recognition of tumor-associated antigens, different from DR molecules, possibly tumor-specific antigens. 相似文献
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TMA-DPH fluorescence decay in human PMN before and after stimulation with FMLP was studied using frequency domain fluorometry. Membrane heterogeneity was assessed by the width of the continuous distributions of lifetime values of Lorentzian shape used to describe the fluorescence decay. In non-stimulated granulocytes TMA-DPH fluorescence decay is characterized by two distributions of lifetime values centered at 6.5 and 1.0 ns and full width at half maximum of 0.3 and 1.2 ns, respectively. Within 15 min after stimulation, the center values of the two distribution components were 5.1 and 0.8 ns and the distribution width was 0.8 and 0.6 ns, respectively. These results indicate changes of membrane domain organization which can be ascribed to compositional changes and redistribution of membrane components. 相似文献
5.
C Fini E Bertoli G Albertini A Floridi F Tanfani 《Biochimica et biophysica acta》1992,1118(2):187-193
Fourier transform infrared spectroscopy (FTIR) was used to investigate the secondary structure of 5'-nucleotidase from bull seminal plasma (BSP). Spectra of protein in both D2O and H2O were analyzed by deconvolution and second derivative methods in order to observe the overlapping components of the amide I band. The protein, which is made up of two apparently identical subunits and which contains two zinc atoms, was studied in its native form, in the presence of dithiotreitol (DTT) and after removal of the two zinc atoms by means of nitrilotriacetic acid (NTA). Deconvolved and second derivative spectra of amide I band showed that the native protein contains mostly beta-sheet structure with a minor content of alpha-helix. The quantitative analysis of the amide I components was performed by a curve-fitting procedure which revealed 54% beta-sheet, 18% alpha-helix, 22% beta-turns and 6% unordered structure. The second derivative and deconvolved spectra of amide I band showed that no remarkable changes in the secondary structure of 5'-nucleotidase were induced by either DTT or NTA. These results were confirmed by the curve-fitting analysis where little or no changes occurred in the relative content of amide I components when the protein was treated with DTT or with NTA. Major changes, however, were observed in the thermal denaturation behavior of the protein. The native protein showed denaturation at temperatures between 70 and 75 degrees C, while the maximum of denaturation was observed between 65 and 70 degrees C and between 55 and 60 degrees C in the presence of NTA and DTT, respectively. The results obtained indicate that the two separate subunits of the protein have essentially the same secondary structure as that of the native enzyme. 相似文献
6.
Dominique Vidaud Michel Tartary Jean-Marc Costa Bruce R. Bahnak Suzana Gispert-Sanchez Edith Fressinaud Claire Gazengel Dominique Meyer Michel Goossens Jean-Maurice Lavergne Michel Vidaud 《Human genetics》1993,91(3):241-244
Mutations in the promoter region of the factor IX gene result in hemophilia B Leyden, which is characterized by considerable improvement in the disease after puberty. We have found that distinct nucleotide substitutions at the -6 position in the Leyden-specific (LS) region are associated with a different severity of hemophilia B. The proband (aged 2) from one family is a severe hemophiliac with factor IX activity (F.IXC) and antigen (F.IXAg) levels less than 1.0U/dl. F.IXC and F.IXAg levels in two affected uncles are approximately 30% of normal levels. The LS region was targeted for analysis because the phenotypes suggested the inheritance of a factor IX Leyden gene. An abnormal TaqI digestion pattern was found in amplified DNA from the proband, and sequencing showed a G (-6) to C transversion that was linked to the disease in the family. In another family, two brothers (aged 8 and 9) suffer from mild hemophilia with F.IXC ranging from 7 to 10 U/dl and F.IXAg from 3 to 4 U/dl. They are the only documented members of the family with a bleeding tendency. Denaturing gradient gel electrophoresis on amplified fragments from one of the patient's genomic DNA corresponding to the 8 exons and flanking sequences of the factor IX gene suggested a defect only in a segment from the 5 region. This segment showed an altered TaqI digestion pattern, and sequencing demonstrated a G(-6) to A transition that was traced to the patients's mother and a grandmother. The different phenotypes associated with the G (-6) to A purine nucleotide transition compared with a G(-6) to C transversion provide evidence that this area is directly involved in the regulation of the human factor IX gene expression in vivo by binding of regulatory factors. The ability to predict that the conditions of a hemophilia B patient will improve with age has important implications for genetic counseling of the family. Therefore, the LS region should always be included when scanning the factor IX gene for mutations. 相似文献
7.
Defenses against oxidative stress in the Antarctic scallop Adamussium colbecki and effects of acute exposure to metals 总被引:5,自引:0,他引:5
Since a general pathway of toxicity induced bypollutants is the enhancement of reactive oxygenspecies, biochemical responses associated withvariations in the antioxidant cellular system havebeen often proposed as biomarkers ofpollutant-mediated toxicity associated with oxidativestress. Antarctic organisms live in an extremeenvironment characterized by low water temperature,high level of dissolved oxygen, presence of ice andstrong seasonal changes in light intensity andavailability of food, conditions which could influenceboth the formation of reactive oxygen species and themechanisms for their removal. In this respect andconsidering the utility of this as a key species formonitoring marine Antarctic environment it was ofinterest to investigate the antioxidant defense systemof the scallop Adamussium colbecki.The parameters examined in the digestive gland of thescallop were the concentration of glutathione and theactivity of several glutathione dependent andantioxidant enzymes (glyoxalase I and II, glutathioneS-transferases, glutathione peroxidases, glutathionereductase, catalase, superoxide dismutase). Very highlevels of catalase suggest a possible adaptation toAntarctic extreme conditions, while the highactivities of glutathione S-transferases are moreprobably related to the feeding behavior of Pectinids.Enzymes from Adamussium colbecki generallyappeared to be active at low temperatures but, with afew exceptions, their activities increased with risingtemperature. Exposure of A. colbecki tosublethal concentrations of Cu or Hg resulted in asignificant reduction in the levels of totalglutathione and in the activity of catalase andglutathione S-transferases. Antioxidant responses ofA. colbecki could represent a useful tool inassessing the biological impact of environmentalpollutants in the Antarctic ecosystems. 相似文献
8.
M Capriotti R Dellantonio P Di Bella F Angeleri E Bertoli G Curatola G Lenaz 《Bollettino della Società italiana di biologia sperimentale》1979,55(11):1028-1032
The transition temperature of erythrocyte ghosts of normal subjects is about 18-20 degrees C. We have studied the viscosity of erythrocyte ghosts of dystrophic children, showing that the transition shifts to lower temperatures (17-18 degrees C). After treatment with erythrocytic compounds like L-Lyso phosphatidyl-Choline dystrophic erythrocytes hemolize at lower Lysophosphatidyl-Choline concentration and at a greater extents than these of normal and carriers subjects. 相似文献
9.
Vasconcelos JL Demétrio DG Santos RM Chiari JR Rodrigues CA Sá Filho OG 《Theriogenology》2006,65(1):192-200
Objectives of this study were to evaluate factors that could affect pregnancy rate after embryo transfer (ET) in lactating dairy cow recipients. The trial was conducted at a dairy farm located in Descalvado, SP, Brazil from October 2003 to September 2004. From 1037 cows with CL that were treated with an injection of PGF2alpha, 43.3% were detected in heat; 263 were previously assigned at day of PGF2alpha injection for AI and 186 for ET. Ovulation rate was 85.7% (385/449). Pregnancy rate for cows with CL for AI and embryo transfer recipients were 36.5% (84/230) and 58.7% (91/155) at day 25 and 33.0% (76/230) and 45.8% (71/155) at day 46, respectively. Embryonic loss were 9.5% (8/84) for the AI group and 21.9% (20/91) for the ET group. Average milk production was 31.4 L/day/cow. Average daily milk production from 7 days before PGF2alpha injection to 7 days after ET tended (P < 0.10) to influence pregnancy rate on days 25 and 46. Average daily milk production from the day of embryo transfer to 7 days after influenced embryonic loss (P < 0.05). Cows with higher milk production had lower probability of pregnancy and higher probability of embryonic loss. Cows with higher days in milk had higher probability of pregnancy. Cows with higher rectal body temperature had lower probability of pregnancy and higher probability of embryonic loss. The influence of high milk yield and body temperature on fertility in lactating dairy cow recipients suggests that these effects can occur also after embryo reaches the blastocyst stage. 相似文献
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